Volke

Since you are low on Submachine Gun HP ammo, and there are only four rockets for the MRL (unless you've already used some), then you're going to want to be using your Handgun for most of the fight. It makes things more difficult, of course, but if you know how to fight it then Nemesis isn't that tough to beat, even on your first time around.

As you probably already know, aim for his head. Keep shooting him with the Handgun unless he's about to hit you, which is when you should either shoot him with your Submachine Gun or the MRL. When he grabs you, you'll also want to use these weapons to prevent him dealing any damage. When he jumps up to the roof, fire way with the Handgun at him until he forces his tentacles through the ground. Fire at the tentacles with your Handgun as they are moving towards you through the ground, as they can deal lots of damage when they get up close. If you have any Grenades left, then use them as they work pretty well. Just make sure he's standing still or walking slowly when you use them.

Repeat this process a few times, and Nemesis shouldn't be to tough to beat.

NOTE - With the exception of this final battle, never shoot Nemesis with anything but the Handgun (except for the part where you have to blow up the Rocket Launcher he's carry, in which case use your Submachine Gun) and try to use the Handgun and Grenades against the zombies.